Citral (3,7 dimethyl 2,6 octadienal) is a major component of lemon smell, and has the sweet-acidulated character of natural lemon. For largely historical reasons, lemon smell has become associated with freshness and cleanliness, both in drinks and in household products, and in fragrances and flavorings, generally. Lemon drinks, whether natural or synthetic, are naturally acid, which causes rapid degradation of citral to unpleasant-smelling products like cresol. This means that the shelf life of lemonade is correspondingly short, creating an expensive logistical problem. In household products, the problem is of a different nature. In order to associate bacteriological cleanliness with the smell of lemon these products frequently use lemon-scented bleach (hypochlorite). Citral is unstable in bleach, and cannot therefore be used. Instead, its nitrile analogue, geranyl nitrile, with its less satisfactory oily-metallic lemon note has to be used.
The chemical instability of citral is largely due to the two double bonds and an aldehyde group, all of which are potentially susceptible to reaction, particularly when used in harsh environments, such as lemon-scented bleach. It would be desirable to develop citral derivatives with improved useful lifetimes, and, preferably, improved odor intensity, while maintaining the lemon note of citral. The present invention provides such citral derivatives.